Scientific American has a fascinating interview with psychologist James Pennebaker about how your use of pronouns can reveal a surprising amount about you.
Much to my surprise, I soon discovered that the ways people used pronouns in their essays predicted whose health would improve the most. Specifically, those people who benefited the most from writing changed in their pronoun use from one essay to another. Pronouns were reflecting people’’s abilities to change perspective.
As I pondered these findings, I started looking at how people used pronouns in other texts — blogs, emails, speeches, class writing assignments, and natural conversation. Remarkably, how people used pronouns was correlated with almost everything I studied. For example, use of first-person singular pronouns (I, me, my) was consistently related to gender, age, social class, honesty, status, personality, and much more. Although the findings were often robust, people in daily life were unable to pick them up when reading or listening to others. It was almost as if there was a secret world of pronouns that existed outside our awareness.
Link to Pennebaker interview in Scientific American (via @bmossop).
Mind Hacks 
It does seem a bit like the second paragraph provides a good reason why we should be sceptical about the first.
If hundreds of background factors (such as age, gender and social class) known to be good predictors of health correlate with language use isn’t it more likely they account for the differences in health rather than the use of pronouns.
This is also worrying if he uses this kind of automatic analysis on college essays as you might end up just excluding people from less priveliged backgrounds.
Quite a scary article. Sounds like Mr Pennebaker found a new way to discriminate against people.